1. Technical Field
The present invention relates to a document display system, a display device, a controller and a computer readable medium.
2. Related Art
A printed matter ordinarily serves to display a fixed image by supplying a coloring material or a developing material such as ink or toner to a medium such as paper. As a medium by which such a medium for fixedly displaying and holding the image can be replaced, a displaying and holding medium has been studied and developed on which an image is formed so as to be rewritten depending on an external wiring force and the formed image is displayed and held even after the external writing force is removed.
Such a displaying and holding medium includes a displaying material for forming the image in a display part as an area for displaying and holding the image. The external writing force (a chemical action such as electric, magnetic, heat, liquid of prescribed PH) is allowed to act on the displaying material, so that the state of the displaying material is physically or chemically changed to form the image corresponding to the external writing force. Further, even after the external writing force is removed, the formed image is maintained. Further, when a different external writing force is allowed to act on the image, the previous image is changed to an image corresponding to the new external writing force. As described above, in view of a point that a displayed state is maintained (stored) under a state that the external writing force is removed, the displaying and holding medium is similar to paper. In addition thereto, in view of a point that the displayed image can be rewritten without externally supplying the coloring material or a developer, the displaying and holding medium is similar to an electronic device. Thus, the displaying and holding medium is referred to as electronic paper.